Breaker arm assembly for a contact set



1965 G. A. DOTTO 3,267,243

BREAKER ARM ASSEMBLY FOR A common sE'r Filed Jan. 27, 1965 2Sheets-Sheet 1 INVENTOR GIA/V/V/ A. DOTTO ATTO R NEY Aug. 16, 1966 s. A.DOTTO 3,267,243

BREAKER ARM ASSEMBLY FOR A CONTACT SET Filed Jan. 27, 1965 2Sheets-Sheet 2 INVENTOR GlA/V/ A. norm ATTORNEY P 3,267,243 Patented Aug1966' 3,267 243 BREAKER ARM ASSEMBEY FOR A CONTACT SET Gianni A. Dotto,Dayton, Ohio, assignor to P. R. Mallory & Co., Inc., Indianapolis, Ind.,acorporation of Dela.

ware

FiledJan.27,1965,Ser.No.428,360

s laims. c1. 200-166) in effectively rotationally centering the contactarm during the process of opening and breaking contacts is avoided.

In the several types of circuit breaker systems heretofore constructed,certain disadvantages have been found. For example, in pivoted breakertype systems, there is the disadvantage that any clearance in the pivotbearing used in the breaker, whether radial or axial clearance, allowsan undesirable variation in the relative alignment of the two contactsduring operation. To keep these clearances within reasonable limits atall temperatures over a reasonable lifetime is an exacting problem ofdesign and production, for as, the life of the contacts progresses,surface irregularities develop on the contacts. Normally, one contactbecomes pitted and the other contact develops a projection of depositedmetal. If these do not always mate exactly, both the performance and thelife of the contacts are adversely affected.

In an attempt to overcome the alignment difficulty, a type of contactorknown as the pivotless contactor has been devised wherein a contact armis held and located by a flat leaf spring. Because there is no lost mo-vtion or friction in the spring itself, there is commonly no diflicultyexperienced with relativealignment of contacts. However, as the springmust be free to bend over some appreciable length, and as the forceexerted by the cam on the arm during the open period is ordinarilyapplied at a different distance from the spring than the force appliedto the contact when closed, there are otten undesirable variations inthe effective center of rotation ofv the contact arm during the processof making or breaking contact. This effect is likely to be mostpronounced at high speeds where inertia forces are relatively large incomparison with static forces. To combat this result, the effectivelength of the spring is made very short. The shortening of the spring,however, results in highly concentrated stresses in the spring andnecessitates very exacting tolerances of forming to maintain propercontact pressure.

It is therefore an object of the present invention to provide a novelignition contact breaker having a construction which provides exactcontact alignment for the breaker and wherein said breaker may bedefinitely angularly positioned so as to provide for an improved highspeed ignition contact make and break system.

It is an object of the present invention to provide a durable ignitioncontact breaker which operates at 'high speeds without chattering orrebounding.

It is an object of the present invention to provide a means foreliminating play at the pivot in order to reduce the spuriousoscillations and contact bounce and thus improve breaker performance.

The invention, in another of its aspects, relates to novel features ofthe instrument-alities described herein for teaching the principalobject of the invention and to the novel principles employed in theinstrumenta-lities whether or not these features and principles may beused in the said object and/ or in the said field.

Otherobjects of the invention and the nature thereof will becomeapparent from the following description considered in conjunction withthe accompanying figures of the drawing and wherein like referencecharacters describe elements of similar function therein and wherein thescope of the invention is determined rather from the dependent claims.

Referring now to the drawings:

FIGURE 1 is a top view of one embodiment of the completed lever.

FIGURE 2 is an isometric view of the breaker arm assembly employed inFIGURE 1.

FIGURE 3 is a crosseectional view of section 33 taken from FIGURE 1.

FIGURE 4 is a cross-sectional view of section 44 taken from FIGUEREFIGURE 5 is a top view of a second embodiment of the completed lever.

FIGURE 6 is an isometric view of the breaker arm assembly employed inFIGURE 5.

FIGURE 7 is a cross-sectional view of section 7-7 taken from FIGURE 5.

FIGURE 8 is a top view of web portion of FIGURE 5.

Generally speaking the present invention provides a durable circuitbreaker lever which operates at high speed without chattering orrebounding of contacts. To accomplish this, a rubber or nylon gasket isforce fitted around the pivot shaft which prevents play in the breakerarm and thus eliminates variation in the contact location. The breakerarm pivots by virtue of the displacement of the material utilized togrip the shaft. The force fitted material is not affected by the varioustemperatures and thus contact is assured at all times.

A circuit breaker 10 comprises breaker arm support plate 11 to whichbreaker arm 12 is to and allowed to rotate by cantilevered shaft 13. Arubber cup or gasket 14 is force fitted around shaft 13 and held inplace by metal cup 15. Spring arm 16 is secured to plate 11 by securingmeans 17 and is secured to breaker arm 12 by U-shaped channel 18 whichis crimped around spring arm 16. An end portion of spring arm 16 issecured in nylon.

rubbing portion 19 for actuating cam. A movable contact 20 is affixed tobreaker arm 12 and a stationary contact 21 is mounted on ear 22 ofsupport plate 11. Open ings 23 and 24 are formed in plate 11 formounting purposes.

In FIGURE 2, it can be seen that spring arm 16 is held I to breaker arm12 in U-shaped channel 18 which is crimped at four points to secure thespring. The channel and crimp eliminate riveting the spring to thebreaker arm as is normally done in devices of this type. The end of thespring 16 has an aperture so that when nylon portion 19 is molded tospring 16, added holding strength is obtained. The relationship betweenspring 16 and portion 19 can be seen in FIGURE 4. Portion 19 alsointerfits with the U-shaped channel and is held by the crimping andpressure from the spring. The interrelation of rubber gasket 14 whichprevents dislocation of shaft 13 (not shown) and metal cup 15 can alsobe seen in FIGURE 2.

I FIGURE 3 shows the shaft assembly in detaiL. Shaft 13 is secured toplate 11 by staking means 23. Rubber cup 14 may be formed in twoportions as is shown in the drawing or in one portion, and is secured bymetal cup 15 which is in two portions and is spot welded at point 26.The metal cup is crimped around the ends of the rubber cup to secure itto the shaft. Washer 25 is part of the securing means 23.

A second embodiment of the present invention is shown in FIGURE 5.Circuit breaker 30 comprises a breaker arm support plate 31. Breaker arm32 is secured to plate 31 by cantilever shaft 33. As can be seen inFIGURE 6, the major portion of breaker arm 32 is a molded nylon portion34. Portion 34 has webbed portion 35 which is force fitted over shaft 33to prevent bouncing and thus prevent contact misalignment. Spring arm 36interfits and is riveted to recessed portion 37 of nylon portion 34,portion 34 being secured to metal portion 44 by the same rivetingprocess at four points, 38, 39, 40 and 41. Contact portion 42 foractuator cam (not shown) is part of molded portion 34. The metal portion44 interfits in channel 43 of nylon portion 34 prior to riveting. Metalportion 44 has a movable contact 45 secured thereto. A stationarycontact 46 is attached to ear 47 of plate 31. The top portion ofspringarm 36 is afiixed by securing means 49. Y 1

In FIGURE 7, webbed portion 35 of molded nylon arm 34 is shown afterbeing force fitted over splined shaft 33. The relation of spring 36 tothe shaft assembly is also shown. Washer 48 separates webbed portion 35from plate 31. Shaft 33 is secured to plate 31 by securing means 50.

0.0016 or A degree.

In both embodiments of the present invention, play in the breaker armwln'ch results in variation in the contact location, and thus chatteringand rebounding of contacts is eliminated by force fitting a rubber ornylon gasket around the pivot shaft. The breaker arm then pivots byvirtue of displacement of the material utilized to grip the shaft. Theforce fitted materials are not affected by various temperatures and thusaccurate contact is assured at all times.

The embodiments of novel invention as hereinabove described are merelyillustrative and not exhaustive in scope and since many widely differentembodiments of the invention may be made without departing from thescope thereof, it is intended that all matter contained in the abovedescription and shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

What is claimed is:

1. An ignition contact set comprising: a bracket having a splined shaftextending upwardly therefrom and rigidly fastened thereto; a resilientplastic hub having an inner hub portion press fitted onto said splinedshaft so as to be secured thereto, an outer hub port-ion, and aplurality of radially spaced integrally formed webs flexibly connectingsaid outer hub portion to said inner hub portion; said outer hub portionhaving an integrally formed portion extending therefrom, said integrallyformed portion having a channel receiving a metal arm, a channelreceiving a leaf spring, and a rubbing block; a moveable contact mountedon said metal arm so as, to be adjacent to a fixed contact mounted onsaid bracket; means securing said metal arm to said integrally formedportion and a first end of said leaf spring so as to electricallyconnect said moveable contact to said leaf spring;

and means securing said second end of said leaf spring to said bracketso as to spring load said moveable contact against said fixed contact.

2. An ignition contact set comprising: a bracket haw 4 ing a shaftextending upwardly therefrom and rigidly fastened thereto; a resilientplastic hub having an inner hub portion affixed to said shaft so as tobe secured thereto, an outer hub portion, and four equally and radiallyspaced integrally formed webs flexibly connecting said outer hub portionto said inner hub portion; said hu-b having an integrally formed portionextending therefrom, said integrally formed portion having a channelreceiving a metal arm,

a channel receiving a leaf spring, and a rubbing block; a moveablecontact mounted on said metal arm so as to be adjacent to a fixedcontact mounted on said bracket; means securing said metal arm to saidintegrally formed portion and a first end of said leaf .spring so as toelectrically connect said moveable contact to said leaf spring; andmeans securing said second end of said leaf spring to said bracket so asto spring load said moveable contact against said fixed contact.

3. In an ignition contact set, a two part breaker arm comprising: amolded plastic portion and a metal portion; said molded plastic portionincluding a webbed hub having an inner hub portion press fitted onto asplined shaft of said contact set, an outer hub portion circumscribingsaid inner hub portion, a plurality of radially spaced integrally formedwebs flexibly connecting said outer hub portion to said inner hubportion, a channel receiving a leaf spring, a channel receiving saidmetal portion, and a rubbing block; said metal portion riveted to saidplastic portion and to said leaf spring; and a contact mounted on saidmetal portion.

4. in an ignition contact set, a two part breaker arm comprising: amolded plastic portion and a metal portion; said molded plastic portionincluding a webbed hub having an inner hub portion press fitted onto asplined shaft of said contact set, an outer hub portion circumscribingsaid inner hub portion, four equally and radially spaced integrallyformed webs connecting said outer hub por-- tion to said inner hubportion so as to permit said outer hub portion to rot-ate with respectto said inner hub portion, a channel receiving a leaf spring, a channelreceiving said metal portion, and a rubbing block; said metal portionriveted to said plastic portion and to said leaf spring; and a contactmounted on said metal portion.

5. In an ignition breaker a two part breaker arm adapted to pivot abouta splined shaft comprising: a molded nylon portion and a metal portion,said nylon portion including a webbed hub portion; a channel receiving aleaf spring, a channel receiving said metal portion, and a rubbingblock; said metal portion riveted to said breaker arm, said rivetsmaking contact between said spring and said metal portion; said metalportion having a movable contact thereon; said webbed hub force fittedover said splined shaft thereby eliminating play in said breaker arm.

References Cited by the Examiner UNITED STATES PATENTS 2,579,523 12/1951Terry 200-166 2,865,755 5/ 1958 [Filko 20030 3,003,043 10/ 1961 'Meyer20030 3,033,947 5/1962 Johnson 200l66 X ROBERT K. SCI-IAEFER, PrimaryExaminer. ROBERT S. MACON, Examiner. H. O. JONES, Assistant Examiner.

5. IN AN IGNITION BREAKER A TWO PART BREAKER ARM ADAPTED TO PIVOT ABOUTA SPLINED SHAFT COMPRISING: A MOLDED NYLON PORTION AND A METAL PORTION,SAID NYLON PORTION INCLUDING A WEBBED HUB PORTION; A CHANNEL RECEIVING ALEAF SPRING, A CHANNEL RECEIVING SAID METAL PORTION AND A RUBBING BLOCK;SAID METAL PORTION RIVETED TO SAID BREAKER ARM, SAID RIVETS MAKINGCONTACT BETWEEN SAID SPRING AND SAID METAL PORTION; SAID METAL PORTIONHAVING